Integrated Pollution Prevention and Control Reference Document on Best Available Techniques in Common Waste Water and Waste Gas Treatment / Management Systems in the Chemical Sector February 2003
EXECUTIVE SUMMARY INTRODUCTION The BREF (Best Available Techniques reference document) on waste water and waste gas treatment and management in the chemical sector reflects an information exchange carried out under Article 16(2) of Council Directive 96/61/EC. This Executive Summary – which is intended to be read in conjunction with the BREF Preface’s explanations of objectives, usage and legal terms – describes the main findings, the principal BAT conclusions and the associated emission levels. It can be read and understood as a stand-alone document but, as a summary, it does not present all the complexities of the full BREF text. It is therefore not intended as a substitute for the full BREF text as a tool in BAT decision making. Waste water and waste gas handling has been identified as a horizontal issue for the chemical sector as it is described in Annex I, 4 of the Directive. It means that the term “Best Available Techniques (BAT)” is assessed in this document for the entire chemical sector, independently of the particular production process(es) and the kind or size of the chemical enterprise(s) involved. It also means that the term BAT needs to include, apart from treatment technologies, a management strategy to achieve optimal waste prevention or control. Thus the scope of the document comprises: • • •
the application of environmental management systems and tools the application of the treatment technology for waste water and waste gas as it is commonly used or applicable in the chemical sector, including the treatment technology for waste water sludge, as long as it is operated on the chemical industry site the identification of or conclusion on best available techniques based on the two preceding items, resulting in a strategy of optimum pollution reduction and, under appropriate conditions, in BAT-associated emission levels at the discharge point to the environment.
Only commonly applied or applicable techniques for the chemical industry are dealt with in this document, leaving process-specific techniques or process-integrated techniques (i.e. nontreatment techniques) to the vertical process BREFs. Though restricted to the chemical industry, it is recognised that the document might also contain valuable information for other sectors (e.g. the refinery sector).
GENERAL ISSUES (CHAPTER 1) Discharges to air and water are the main environmental impacts caused by releases from chemical installations. The main sources of waste water in the chemical industry are: • • • • • • • •
chemical syntheses waste gas treatment systems conditioning of utility water bleed from boiler feed water systems blowdown from cooling cycles backwashing of filters and ion exchangers landfill leachates rainwater from contaminated areas, etc.,
Waste Water and Waste Gas Treatment
their main impact being characterised by: • • • •
hydraulic load content of pollutant substances (expressed as load or concentration) effect or hazardous potential on the receiving water body, expressed as surrogate or sum parameters effect on organisms in the receiving water body, expressed as toxicity data.
Waste gas emissions appear as: • • •
ducted emissions, which are the only emissions that can be treated diffuse emissions fugitive emissions.
The main air pollutants are: • • • • • •
VOCs sulphur compounds (SO2, SO3, H2S, CS2, COS) nitrogen compounds (NOx, N2O, NH3, HCN) halogen compounds (Cl2, Br2, HF, HCl, HBr) incomplete combustion compounds (CO, CxHy) particulate matter.
MANAGEMENT SYSTEMS AND TOOLS (CHAPTER 2) Environmental management is a strategy for dealing with waste releases (or their pre